Much of the information we learn comes from authority figures (including teachers, authors, parents, highly qualified personnel). This should not be surprising in such a diverse society. It is normal to take the word of a Nobel Laureate over a known con artist. This is an extreme example but the point is it makes sense to take the word of someone who has been right in the past and has shown a high level of knowledge in a specific domain. The problem occurs when we begin to rely too heavily on authority. Authority may provide a hint to what’s right but authorities are fallible. A logical fallacy referred to as Appeal to Authority (Argument by Authority, Argument from Authority) occurs when the truth-value of the assertion is based on the authority. There are two types of Appeal to Authority: 1) this form of the appeal to authority is when a person presenting a position on a subject mentions some authority who also holds that position, but who is not actually an authority in that area; 2) the second form, citing a person who is actually an authority in the relevant field, carries more weight. Many authorities have a greater knowledge of some subject than other people, and they should be trusted too a degree (but they are still fallible). On the other end, you don’t need to be a recognized authority to be right. Evidence is the ultimate source of authority. If the authority cannot provide valid evidence for their claims, disregard them. Don’t be afraid to use what Huxley refered to in A Liberal Education as “The Mental Power”. He describes it as that "which will be of most importance in your...life will be the power of seeing things as they are without regard to authority...But at school and at college, you shall know of no source of truth but authority."

Thoughts on Authority

“One of the greatest commandments of science is, “Mistrust arguments from authority.” (Scientists, being primates, and thus given to dominance hierarchies, of course do not always follow this commandment.) Too many such arguments have proved too painfully wrong. Authorities must prove their contentions like everybody else. This independence of science, its occasional unwillingness to accept conventional wisdom, makes it dangerous to doctrines less self-critical, or with pretensions to certitude” (pg. 28 Demon Haunted World). Carl Sagan

“Arguments from authority carry little weight (in science there are no "authorities’)”Carl Sagan

“Who is making the claim makes a difference. If it is a Nobel laureate, we take note because he or she has been right in a big way before. If it is a discredited scam artist, we give a loud guffaw because he or she has been wrong in a big way before. While expertise is useful for separating the wheat from the chaff, it is dangerous in that we might either 1) accept a wrong idea just because it was supported by someone we respect (false positive) or 2) reject a right idea just because it was supported by someone we disrespect (false negative). How do you avoid such errors? Examine the evidence” (pg. 57 Why People Believe Weird Things).Michael Shermer

“After we look for the evidence we have to judge the evidence. There are the usual rules about the judging the evidence; it’s not right to pick only what you like, but to take all of the evidence, to try to maintain some objectivity about the thing-enough to keep the thing going-not to ultimately depend upon authority. Authority may be a hint as to what the truth is, but is not the source of information. As long as it’s possible, we should disregard authority whenever the observations disagree with it” (pg.104 The Pleasure of Finding things Out).Richard P. Feynman

Authority is not the ultimate source of truth. I would agree with John Stuart Mill in suggesting there is no “absolute certainty”. The degree of certainty increases when supported by evidence. If the authority is a real authority they should have no problem providing evidence to support their claims. If they fail to provide evidence, avoid questions, launch personal attacks and consistently mention their diploma, certificate, etc when questioned you can probably conclude they are what I call Paper Gurus.